What is Verapamil used for?

Verapamil: Clinical Uses and Indications

Verapamil is a calcium channel blocker primarily used for the treatment of hypertension, management of supraventricular tachycardias, and treatment of angina pectoris. 1, 2

Primary Indications

• Hypertension: Verapamil is FDA-approved for the treatment of hypertension to lower blood pressure, reducing the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions 2
• Supraventricular Tachycardia (SVT): Verapamil is effective for acute termination of PSVT when adenosine fails or is contraindicated, with a recommended dose of 2.5-5 mg IV bolus over 2 minutes 3, 4
• Angina Pectoris: Verapamil is effective in the management of stable angina pectoris, with efficacy comparable to beta-blockers like propranolol or metoprolol 5

Mechanism of Action

• Verapamil antagonizes calcium influx through slow channels in vascular smooth muscle and cardiac cell membranes 6
• It reduces intracellular free calcium concentrations, causing coronary and peripheral vasodilation 6
• In the heart, verapamil slows AV node conduction and increases AV node refractoriness, making it effective for certain arrhythmias 3, 7

Dosing Information

For Hypertension:

• Initial oral dose: 120 mg daily, which can be titrated up to a maximum of 480 mg daily 3
• Sustained-release formulations allow for once-daily dosing with similar efficacy to conventional formulations given three times daily 6

For Acute SVT:

• Initial dose: 2.5-5 mg IV bolus over 2 minutes 3, 4
• If no response, additional 5-10 mg can be given every 15-30 minutes to a maximum total dose of 20-30 mg 3, 4

Special Considerations and Contraindications

• Contraindicated in:

  • AV block greater than first degree (unless pacemaker present) 3
  • SA node dysfunction 3
  • Decompensated heart failure or severe LV dysfunction 1, 3
  • Hypotension or cardiogenic shock 3
  • Wolff-Parkinson-White syndrome with atrial fibrillation/flutter 3
  • Patients who have recently received beta-blockers (risk of profound bradycardia) 3, 4

• Use with caution in:

  • Elderly patients (administer IV over 3 minutes) 3
  • Patients with hypertrophic cardiomyopathy 4

Clinical Pearls

• Verapamil is particularly effective for idiopathic left ventricular tachycardia (fascicular VT), which has a verapamil-sensitive reentrant mechanism 1
• Unlike beta-blockers, verapamil does not cause bronchoconstriction, making it suitable for patients with asthma or chronic obstructive airway disease 6
• Verapamil does not typically cause reflex tachycardia, orthostatic hypotension, or development of tolerance 6
• Common side effects include constipation, hypotension, bradycardia, and leg edema 4, 8

Comparative Efficacy

• As a first-line antihypertensive agent, verapamil is comparable in efficacy to other calcium antagonists, beta-blockers, diuretics, ACE inhibitors, and other vasodilators 6
• In the INVEST trial, verapamil-based treatment showed similar outcomes to atenolol-based treatment in hypertensive patients with coronary artery disease 1
• Verapamil has been shown to reduce mortality and reinfarction rates after acute myocardial infarction in patients without heart failure, with reductions similar to those achieved with beta-blockers 5

Combination Therapy

• Verapamil produces marked blood pressure reductions when combined with diuretics, ACE inhibitors, beta-blockers, and vasodilators in patients with refractory hypertension 6
• Long-acting dihydropyridine agents are preferred over verapamil for use in combination with beta-blockers to avoid excessive bradycardia or heart block 1